SHFileOperation Problem in C# (FOF_SIMPLEPROGRESS )

[narsys]

I'm using SHFileOperation in my project. Everything is ok but something goes wrong when I want to use FOF_SIMPLEPROGR ESS falg. when I set it it doesn't work. I can't see nothing! if I use ansi version(without CharSet) it generates an exception!!

here is my code:

        [StructLayout(LayoutKind.Sequential,CharSet=CharSet.Unicode)]
        public struct SHFILEOPSTRUCT
        {
            public IntPtr hwnd;
            public UInt32 wFunc;
            [MarshalAs(UnmanagedType.LPWStr)]public string pFrom;
            [MarshalAs(UnmanagedType.LPWStr)]public string pTo;
            public UInt16 fFlags;
            public Int32 fAnyOperationsAborted;
            public IntPtr hNameMappings;
            [MarshalAs(UnmanagedType.LPWStr)]public string lpszProgressTitle;
        }        
public class FileOperation
{
      public const UInt16 FO_MOVE = 0x0001;
      public const UInt16 FO_COPY = 0x0002;
      public const UInt16 FO_DELETE = 0x0003;
      public const UInt16 FO_RENAME = 0x0004;
}

public class FILEOP_FLAGS
{

     public const UInt16 FOF_MULTIDESTFILES = 0x0001;
     public const UInt16 FOF_CONFIRMMOUSE = 0x0002;
     public const UInt16 FOF_SILENT = 0x0004;  // don't create progress/report
     public const UInt16 FOF_RENAMEONCOLLISION = 0x0008;
     public const UInt16 FOF_NOCONFIRMATION = 0x0010; 
     public const UInt16 FOF_WANTMAPPINGHANDLE = 0x0020;             
     public const UInt16 FOF_ALLOWUNDO = 0x0040;
     public const UInt16 FOF_FILESONLY = 0x0080; // on *.*, do only files
     public const UInt16 FOF_SIMPLEPROGRESS = 0x0100; 
     public const UInt16 FOF_NOCONFIRMMKDIR = 0x0200; 
     public const UInt16 FOF_NOERRORUI = 0x0400; // don't put up error UI
     public const UInt16 FOF_NOCOPYSECURITYATTRIBS = 0x0800; 
     public const UInt16 FOF_NORECURSION = 0x1000;     
     public const UInt16 FOF_NO_CONNECTED_ELEMENTS = 0x2000; 
     public const UInt16 FOF_WANTNUKEWARNING = 0x4000;          
     public const UInt16 FOF_NORECURSEREPARSE = 0x8000;
}

[DllImport("Shell32.dll", CharSet = CharSet.Unicode)]
public static extern int SHFileOperation([MarshalAs(UnmanagedType.Struct)]ref SHFILEOPSTRUCT lpFileOp);

I'm using it like this:

FileFolder.SHFILEOPSTRUCT str = new FileFolder.SHFILEOPSTRUCT();
            
str.fFlags =  FileFolder.FILEOP_FLAGS.FOF_SIMPLEPROGRESS;
str.pFrom = "c:\\test1.txt\0\0";
str.pTo = "d:\\test1.txt\0\0";
str.hwnd = this.Handle;
str.fAnyOperationsAborted = 0;
str.hNameMappings = IntPtr.Zero;
//it does'nt apper in the dialog box
str.lpszProgressTitle = "yesssssssssssssss";
str.wFunc = FileFolder.FileOperation.FO_COPY;
FileFolder.SHFileOperation(ref str);
if (str.fAnyOperationsAborted!=0)
{
        MessageBox.Show("Abroted");
}